<template>
  <div>
    <router-link
      tag="div"
      to="/"
      class="header-abs"
      v-show="showAbs"
    >
      <span class="inconfont header-abs-back">&#xe624;</span>
    </router-link>
    <div
      class="header-fixed"
      v-show="!showAbs"
    >
      <router-link tag="div" to="/" class="header-abs">
        <span class="inconfont header-fixed-back">&#xe624;</span>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
  export default {
    name: "DetailHeader",
    data () {
      return {
        showAbs: true,
        opacityStyle: {
          opacity: 0
        }
      }
    },
    methods: {
      handleScroll () {
        // console.log(document.documentElement.scrollTop)
        const top = document.documentElement.scrollTop
        if (top > 60) {
          let opacity = top / 140
          opacity = opacity > 1 ? 1 : opacity
          this.opacityStyle = {opacity}
          this.showAbs = false
        } else {
          this.showAbs = true
        }
      }
    },
    mounted () {
      window.addEventListener('scroll',this.handleScroll)
   },
    //下面方法解决解绑全局定义
    deactivated() {
      window.addEventListener('scroll',this.handleScroll)
    }
  }
</script>

<style lang="stylus" scoped>
  @import "~style/varibles.styl"
  .header-abs
    position: absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .8rem
    border-radius: .4rem
    text-align: center
    background: rgba(0, 0, 0, .8)

    .header-abs-back
      color: #ffffff
      font-size: .4rem

  .header-fixed
    z-index:2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #ffffff
    background: $bgColor
    font-size: .32rem

  .header-fixed-back
    position: absolute
    top: 0
    left: 0
    width: .64rem
    text-align: center
    font-size: .4rem
    color: #ffffff
</style>
